A parameter frequently used to characterize the acceleration of vehicles and, in conjunction with closed-loop random vibration controllers, to simulate the transport environment is the power spectral density (PSD) estimate. The vertical acceleration experienced by the loading tray of road transport vehicles is primarily a function of the type of suspension, load, vehicle speed, and road surface characteristics. The first three parameters can vary considerably between and during journeys, whereas statistical parameters used to describe road surface profiles are less susceptible to change with time. The authors of this paper present a brief analysis and discussion of the spectral and statistical characteristics of actual road surface elevation records. The deviation of the road profile distribution from the Gaussian distribution is observed, and it is revealed that roads of different roughness seem to retain their spectral shape. Also, an array of statistical parameters are introduced and recommended for use in the classification of road profiles. A method is demonstrated in which a random vibration controller is used to simulate road profile spectra by controlling the displacement instead of the acceleration of a shaker table. To account for the dynamic characteristics of the vehicle, the method uses a physical model of a vehicle suspension. The use of digital signal processors (DSP) together with a time domain adaptive filter control technique for the accurate reproduction of synthesized demand signals is presented as well.


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  • Accession Number: 00721058
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: May 3 1996 12:00AM